The present invention relates generally to tools for removing retaining rings, and more particularly, to a tool for removing internally and externally mounted retaining rings.
Retaining rings are commonly used in various industries to retain parts either within a cylindrical bore or on a cylindrical shaft. One type of retaining ring is a spiral retaining ring formed from one or more turns of flat wire which is wound in a spiral fashion upon itself to form multiple turns. The ends of the wire may include specially cut out portions that permit the ends to be grabbed by a pliers.
It is difficult to grab the free ends of the retaining rings due to the size of the bore and the clearance of the shaft. Further difficulty is encountered in that one of the free ends must be lifted from the remainder of the ring with a blunt object such as a screw driver or a fine point object, such as a dental pick, and then grabbed by the user so that the free ends and its turn may be unwound, further unwinding results in removal of the ring from the bore or shaft groove. Often these "pry-type" tools will slip out of engagement with the free end, frustrating the user and potentially causing injury when the pry tool becomes disengaged from the ring free end.
Various tools have been developed to remove snap rings and other types of rings. One of these tools, as described in U.S. Pat. No. 4,689,865 which issued Sep. 1, 1987, has a pliers-like body with two free ends that engage the free ends of the snap ring. This tool is complex and difficult to construct. It also can only be used in a perpendicular orientation with the snap ring. A similar tool is described in U.S. Pat. No. 5,212,859 issued May 25, 1993, whereupon the free ends of the tool are engaged with the free ends of the ring and then moved apart under the urging of the handles. The user must have sufficient clearance to attach the tool and to manipulate the handles of the tool.
U.S. Pat. No. 4,175,310 issued Nov. 27, 1979, describes a snap ring removal tool that does not use a pliers-type structure and thus can be operated with one hand from either the interior or exterior of a snap ring. However, the tool must be seated against either the interior of the bore or exterior of the shaft. If this contact is not maintained during the removal of ring, the tool can slip and lose its engagement with the free end of the snap ring.
U.S. Pat. No. 4,757,591 issued Jul. 17, 1988, describes a similar rotatable snap ring removal tool that incorporates a complex clamping end that first clamps the free end of a snap ring so that it may be removed from its groove and a separate pry tool inserted between the ring end and the bore. This construction is both complex and cumbersome.
These prior art tools all have various engagement and/or clamping ends for engaging free ends of single turn rings and they could not be easily adapted to engage a free end of a multiple turn ring. The present invention is therefore directed to a removal tool that can be easily operated with one hand and that is useful with both single turn and multiple turn retaining rings and which overcomes the aforementioned disadvantages.